Simulation And Optimization Of Energy Management Strategy For Parallel HEV Based On Dynamic Programming

To solve the problems of energy shortages and environmental pollution,some new technologies of power system and new energy vehicles have been extensively concerned and rapidly developed.Based on the combustion characteristics of hydrogen,a lean-burn gasoline engine with hydrogen direct injection and local hydrogen-enrichment is proposed in this paper.After adding hydrogen,gasoline combustion is promoted,moreover,fuel consumptions are improved and exhaust emissions are reduced significantly.In order to further exploit the advantages of hydrogen-blended gasoline engine and explore the technology of energy-saving,the hydrogen-blended gasoline engine is used in a parallel hybrid electric vehicle.In this paper,dynamic programming algorithm will be used to solve the optimization of energy management strategy of HEV.The results of the dynamic programming algorithm are used to improve the initial energy management strategy and the energy management strategy after optimizing is used for simulation of vehicle performance.The main contents include:This paper analyzed the different configurations of hybrid vehicles,and determined the double-shaft parallel hybrid vehicle as the research object,which is refitted on the basis of Jeep BJ2023.And the parameters were chosen and matched according to the requirements of power performance.On the basis of the parallel hybrid vehicle model which ADVISOR2002 offers,the model of double-shaft parallel hybrid vehicle with hydrogen-blended gasoline engine is established with MATLAB/Simulink.The vehicle definition files and the data files of vehicle components were created and the vehicle parameters were set up on ADVISOR2002.Then,simulation model of vehicle was built.Dynamic programming can transform complex global optimal problems into single-stage decision problems.The energy management strategy of parallel hybrid electric vehicle is optimized based on dynamic programming.The cost function aiming at the lowest fuel consumption rate is established and the rationality of the cost function is verified.The optimal energy management strategy is calculated by four steps: variable discretization,feasible interval determination,precomputing fuel consumption matrix and solving cost function.This optimal energy management strategy can achieve the best fuel economy as well as meet the system constraints.The optimal energy management strategy solved by the dynamic programming algorithm cannot be applied to the on-line control of hybrid vehicle.Therefore,it is necessary to extract effective rules including power split rules and shift rules from the optimal strategy and use them to improve the initial control strategy of parallel hybrid electric vehicle which ADVISOR2002 offers.After the improved control strategy was embedded into the control model,and the simulation of fuel economy and emissions was carried out on the simulation platform.The simulation results show that the characteristics of fuel economy and emissions of hybrid electric vehicle with hydrogen-blended gasoline engine are greatly improved compared with the ordinary hybrid electric vehicle.The fuel consumptions applied improved control strategy based on the dynamic programming is 9.1% less than that of initial control strategy,which indicate that the dynamic programming has played an effective role in the optimization of vehicle energy management strategy.